Chroma signals derived, for example, from a pick-up tube, a magnetic tape, or the like, usually provide three signals R, G, B (red, green, blue). A matrix circuit is used to provide color difference signals (R-Y) and (B-Y) and a luminance signal (Y). Three transistor stages may be used in such a circuit.
German Pat. No. 24, 13 025, by the inventor hereof, describes a circuit of this type.